Calendar [React Day Picker]

"use client";

import { cn } from "@/lib/utils";
import { Calendar } from "@/components/ui/calendar";
import { format } from "date-fns";
import { useEffect, useState } from "react";
import { DayButtonProps } from "react-day-picker";

const GOOD_PRICE_THRESHOLD = 100;

function Component() {
  const today = new Date();
  const [date, setDate] = useState<Date | undefined>(today);

  const [mockPriceData, setMockPriceData] = useState<Record<string, number>>({});
  useEffect(() => {
    const generateMockPriceData = () => {
      const data: Record<string, number> = {};

      for (let i = 0; i < 180; i++) {
        const date = new Date(today);
        date.setDate(today.getDate() + i);
        const dateKey = format(date, "yyyy-MM-dd");
        const randomPrice = Math.floor(Math.random() * (200 - 80 + 1)) + 80;
        data[dateKey] = randomPrice;
      }
      return data;
    };
    setMockPriceData(generateMockPriceData());
  }, []);

  const isDateDisabled = (date: Date) => {
    return !mockPriceData[format(date, "yyyy-MM-dd")];
  };

  return (
    <div>
      <Calendar
        mode="single"
        selected={date}
        onSelect={setDate}
        numberOfMonths={2}
        pagedNavigation
        showOutsideDays={false}
        className="rounded-lg border border-border p-2 bg-background"
        classNames={{
          months: "sm:flex-col md:flex-row gap-8",
          month:
            "relative first-of-type:before:hidden before:absolute max-md:before:inset-x-2 max-md:before:inset-y-2 md:before:w-px before:bg-border md:before:-left-4",
          weekday: "w-12",
          day_button: "size-12",
          today: "*:after:hidden",
        }}
        components={{
          DayButton: (props: DayButtonProps) => <DayButton {...props} prices={mockPriceData} />,
        }}
        disabled={isDateDisabled}
      />
      <p
        className="mt-4 text-center text-xs text-muted-foreground"
        role="region"
        aria-live="polite"
      >
        Pricing calendar -{" "}
        <a
          className="underline hover:text-foreground"
          href="https://daypicker.dev/"
          target="_blank"
          rel="noopener nofollow"
        >
          React DayPicker
        </a>
      </p>
    </div>
  );
}

function DayButton(props: DayButtonProps & { prices: Record<string, number> }) {
  const { day, modifiers, prices, ...buttonProps } = props;
  const price = prices[format(day.date, "yyyy-MM-dd")];
  const isGoodPrice = price < GOOD_PRICE_THRESHOLD;

  return (
    <button {...buttonProps}>
      <span className="flex flex-col">
        {props.children}
        {price && (
          <span
            className={cn(
              "text-[10px] font-medium",
              isGoodPrice
                ? "text-emerald-500"
                : "text-muted-foreground group-data-[selected]:text-primary-foreground/70",
            )}
          >
            ${price}
          </span>
        )}
      </span>
    </button>
  );
}

export { Component };